/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.micode.notes.ui;

import java.text.DateFormatSymbols;
import java.util.Calendar;

import net.micode.notes.R;

import android.content.Context;
import android.text.format.DateFormat;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.NumberPicker;

/**
 * 自定义的日期时间选择器组件。
 * 提供日期、小时、分钟和AM/PM的选择功能。
 */
public class DateTimePicker extends FrameLayout {

    // 常量定义，用于限制控件选择的值
    private static final boolean DEFAULT_ENABLE_STATE = true;
    private static final int HOURS_IN_HALF_DAY = 12;  // 半天小时数
    private static final int HOURS_IN_ALL_DAY = 24;   // 一天的小时数
    private static final int DAYS_IN_ALL_WEEK = 7;    // 一周的天数
    private static final int DATE_SPINNER_MIN_VAL = 0; // 日期选择器最小值
    private static final int DATE_SPINNER_MAX_VAL = DAYS_IN_ALL_WEEK - 1;  // 日期选择器最大值
    private static final int HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW = 0;  // 24小时制小时选择器最小值
    private static final int HOUR_SPINNER_MAX_VAL_24_HOUR_VIEW = 23; // 24小时制小时选择器最大值
    private static final int HOUR_SPINNER_MIN_VAL_12_HOUR_VIEW = 1;  // 12小时制小时选择器最小值
    private static final int HOUR_SPINNER_MAX_VAL_12_HOUR_VIEW = 12; // 12小时制小时选择器最大值
    private static final int MINUT_SPINNER_MIN_VAL = 0;  // 分钟选择器最小值
    private static final int MINUT_SPINNER_MAX_VAL = 59; // 分钟选择器最大值
    private static final int AMPM_SPINNER_MIN_VAL = 0;    // AM/PM选择器最小值
    private static final int AMPM_SPINNER_MAX_VAL = 1;    // AM/PM选择器最大值

    // 控件定义
    private final NumberPicker mDateSpinner;  // 日期选择器
    private final NumberPicker mHourSpinner;  // 小时选择器
    private final NumberPicker mMinuteSpinner; // 分钟选择器
    private final NumberPicker mAmPmSpinner;  // AM/PM选择器
    private Calendar mDate;  // 存储当前日期和时间的 Calendar 对象

    // 日期显示的值数组
    private String[] mDateDisplayValues = new String[DAYS_IN_ALL_WEEK];

    // 当前是 AM 还是 PM
    private boolean mIsAm;

    // 是否为 24 小时制
    private boolean mIs24HourView;

    // 控件是否可用
    private boolean mIsEnabled = DEFAULT_ENABLE_STATE;

    // 初始化状态
    private boolean mInitialising;

    // 日期时间变化监听器
    private OnDateTimeChangedListener mOnDateTimeChangedListener;

    // 日期选择器值变化监听器
    private NumberPicker.OnValueChangeListener mOnDateChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            // 更新日期
            mDate.add(Calendar.DAY_OF_YEAR, newVal - oldVal);
            updateDateControl();  // 更新日期选择器
            onDateTimeChanged();  // 通知日期时间变化
        }
    };

    // 小时选择器值变化监听器
    private NumberPicker.OnValueChangeListener mOnHourChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            boolean isDateChanged = false;
            Calendar cal = Calendar.getInstance();
            if (!mIs24HourView) {
                // 12小时制模式下，处理AM/PM的变化
                if (!mIsAm && oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY) {
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, 1);
                    isDateChanged = true;
                } else if (mIsAm && oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, -1);
                    isDateChanged = true;
                }
                if (oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY ||
                        oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {
                    mIsAm = !mIsAm;
                    updateAmPmControl();  // 更新AM/PM选择器
                }
            } else {
                // 24小时制模式下，处理日期变化
                if (oldVal == HOURS_IN_ALL_DAY - 1 && newVal == 0) {
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, 1);
                    isDateChanged = true;
                } else if (oldVal == 0 && newVal == HOURS_IN_ALL_DAY - 1) {
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, -1);
                    isDateChanged = true;
                }
            }
            // 更新小时
            int newHour = mHourSpinner.getValue() % HOURS_IN_HALF_DAY + (mIsAm ? 0 : HOURS_IN_HALF_DAY);
            mDate.set(Calendar.HOUR_OF_DAY, newHour);
            onDateTimeChanged();  // 通知日期时间变化
            // 如果日期发生变化，更新年份、月份、日期
            if (isDateChanged) {
                setCurrentYear(cal.get(Calendar.YEAR));
                setCurrentMonth(cal.get(Calendar.MONTH));
                setCurrentDay(cal.get(Calendar.DAY_OF_MONTH));
            }
        }
    };

    // 分钟选择器值变化监听器
    private NumberPicker.OnValueChangeListener mOnMinuteChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            // 更新分钟
            mDate.set(Calendar.MINUTE, newVal);
            onDateTimeChanged();  // 通知日期时间变化
        }
    };

    // AM/PM选择器值变化监听器
    private NumberPicker.OnValueChangeListener mOnAmPmChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            mIsAm = !mIsAm;
            // 根据AM/PM的选择，调整小时
            if (mIsAm) {
                mDate.add(Calendar.HOUR_OF_DAY, -HOURS_IN_HALF_DAY);
            } else {
                mDate.add(Calendar.HOUR_OF_DAY, HOURS_IN_HALF_DAY);
            }
            updateAmPmControl();  // 更新AM/PM控制
            onDateTimeChanged();  // 通知日期时间变化
        }
    };

    // 日期时间变化监听器接口
    public interface OnDateTimeChangedListener {
        void onDateTimeChanged(DateTimePicker view, int year, int month,
                               int dayOfMonth, int hourOfDay, int minute);
    }

    // 构造函数，初始化日期时间选择器
    public DateTimePicker(Context context) {
        this(context, System.currentTimeMillis());
    }

    // 构造函数，初始化日期时间选择器，并传入日期
    public DateTimePicker(Context context, long date) {
        this(context, date, DateFormat.is24HourFormat(context));
    }

    // 构造函数，初始化日期时间选择器，并传入日期和是否24小时制
    public DateTimePicker(Context context, long date, boolean is24HourView) {
        super(context);
        mDate = Calendar.getInstance();
        mInitialising = true;
        mIsAm = getCurrentHourOfDay() >= HOURS_IN_HALF_DAY;
        inflate(context, R.layout.datetime_picker, this); // 加载自定义布局

        // 初始化日期选择器控件
        mDateSpinner = (NumberPicker) findViewById(R.id.date);
        mDateSpinner.setMinValue(DATE_SPINNER_MIN_VAL);
        mDateSpinner.setMaxValue(DATE_SPINNER_MAX_VAL);
        mDateSpinner.setOnValueChangedListener(mOnDateChangedListener);

        // 初始化小时选择器控件
        mHourSpinner = (NumberPicker) findViewById(R.id.hour);
        mHourSpinner.setOnValueChangedListener(mOnHourChangedListener);
        
        // 初始化分钟选择器控件
        mMinuteSpinner = (NumberPicker) findViewById(R.id.minute);
        mMinuteSpinner.setMinValue(MINUT_SPINNER_MIN_VAL);
        mMinuteSpinner.setMaxValue(MINUT_SPINNER_MAX_VAL);
        mMinuteSpinner.setOnLongPressUpdateInterval(100);
        mMinuteSpinner.setOnValueChangedListener(mOnMinuteChangedListener);

        // 初始化AM/PM选择器控件
        String[] stringsForAmPm = new DateFormatSymbols().getAmPmStrings();
        mAmPmSpinner = (NumberPicker) findViewById(R.id.amPm);
        mAmPmSpinner.setMinValue(AMPM_SPINNER_MIN_VAL);
        mAmPmSpinner.setMaxValue(AMPM_SPINNER_MAX_VAL);
        mAmPmSpinner.setDisplayedValues(stringsForAmPm);
        mAmPmSpinner.setOnValueChangedListener(mOnAmPmChangedListener);

        // 更新控件为初始状态
        updateDateControl();
        updateHourControl();
        updateAmPmControl();

        // 设置24小时制模式
        set24HourView(is24HourView);

        // 设置当前时间
        setCurrentDate(date);

        setEnabled(isEnabled());  // 设置是否启用

        // 设置控件的内容描述
        mInitialising = false;
    }

    @Override
    public void setEnabled(boolean enabled) {
        if (mIsEnabled == enabled) {
            return;
        }
        super.setEnabled(enabled);
        mDateSpinner.setEnabled(enabled);
        mMinuteSpinner.setEnabled(enabled);
        mHourSpinner.setEnabled(enabled);
        mAmPmSpinner.setEnabled(enabled);
        mIsEnabled = enabled;
    }

    @Override
    public boolean isEnabled() {
        return mIsEnabled;
    }

    // 获取当前日期的时间戳
    public long getCurrentDateInTimeMillis() {
        return mDate.getTimeInMillis();
    }

    // 设置当前日期时间
    public void setCurrentDate(long date) {
        Calendar cal = Calendar.getInstance();
        cal.setTimeInMillis(date);
        setCurrentDate(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH),
                cal.get(Calendar.HOUR_OF_DAY), cal.get(Calendar.MINUTE));
    }

    // 设置当前日期和时间
    public void setCurrentDate(int year, int month, int dayOfMonth, int hourOfDay, int minute) {
        setCurrentYear(year);
        setCurrentMonth(month);
        setCurrentDay(dayOfMonth);
        setCurrentHour(hourOfDay);
        setCurrentMinute(minute);
    }

    // 获取当前年份
    public int getCurrentYear() {
        return mDate.get(Calendar.YEAR);
    }

    // 设置当前年份
    public void setCurrentYear(int year) {
        if (!mInitialising && year == getCurrentYear()) {
            return;
        }
        mDate.set(Calendar.YEAR, year);
        updateDateControl();
        onDateTimeChanged();
    }

    // 获取当前月份
    public int getCurrentMonth() {
        return mDate.get(Calendar.MONTH);
    }

    // 设置当前月份
    public void setCurrentMonth(int month) {
        if (!mInitialising && month == getCurrentMonth()) {
            return;
        }
        mDate.set(Calendar.MONTH, month);
        updateDateControl();
        onDateTimeChanged();
    }

    // 获取当前日期
    public int getCurrentDay() {
        return mDate.get(Calendar.DAY_OF_MONTH);
    }

    // 设置当前日期
    public void setCurrentDay(int dayOfMonth) {
        if (!mInitialising && dayOfMonth == getCurrentDay()) {
            return;
        }
        mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
        updateDateControl();
        onDateTimeChanged();
    }

    // 获取当前小时（24小时制）
    public int getCurrentHourOfDay() {
        return mDate.get(Calendar.HOUR_OF_DAY);
    }

    // 获取当前小时（12小时制或24小时制）
    private int getCurrentHour() {
        if (mIs24HourView){
            return getCurrentHourOfDay();
        } else {
            int hour = getCurrentHourOfDay();
            if (hour > HOURS_IN_HALF_DAY) {
                return hour - HOURS_IN_HALF_DAY;
            } else {
                return hour == 0 ? HOURS_IN_HALF_DAY : hour;
            }
        }
    }

    // 设置当前小时（24小时制）
    public void setCurrentHour(int hourOfDay) {
        if (!mInitialising && hourOfDay == getCurrentHourOfDay()) {
            return;
        }
        mDate.set(Calendar.HOUR_OF_DAY, hourOfDay);
        if (!mIs24HourView) {
            if (hourOfDay >= HOURS_IN_HALF_DAY) {
                mIsAm = false;
                if (hourOfDay > HOURS_IN_HALF_DAY) {
                    hourOfDay -= HOURS_IN_HALF_DAY;
                }
            } else {
                mIsAm = true;
                if (hourOfDay == 0) {
                    hourOfDay = HOURS_IN_HALF_DAY;
                }
            }
            updateAmPmControl();
        }
        mHourSpinner.setValue(hourOfDay);
        onDateTimeChanged();
    }

    // 获取当前分钟
    public int getCurrentMinute() {
        return mDate.get(Calendar.MINUTE);
    }

    // 设置当前分钟
    public void setCurrentMinute(int minute) {
        if (!mInitialising && minute == getCurrentMinute()) {
            return;
        }
        mMinuteSpinner.setValue(minute);
        mDate.set(Calendar.MINUTE, minute);
        onDateTimeChanged();
    }

    // 判断是否为24小时制
    public boolean is24HourView () {
        return mIs24HourView;
    }

    // 设置是否为24小时制或AM/PM制
    public void set24HourView(boolean is24HourView) {
        if (mIs24HourView == is24HourView) {
            return;
        }
        mIs24HourView = is24HourView;
        mAmPmSpinner.setVisibility(is24HourView ? View.GONE : View.VISIBLE);
        int hour = getCurrentHourOfDay();
        updateHourControl();
        setCurrentHour(hour);
        updateAmPmControl();
    }

    // 更新日期选择器的显示内容
    private void updateDateControl() {
        Calendar cal = Calendar.getInstance();
        cal.setTimeInMillis(mDate.getTimeInMillis());
        cal.add(Calendar.DAY_OF_YEAR, -DAYS_IN_ALL_WEEK / 2 - 1);
        mDateSpinner.setDisplayedValues(null);
        for (int i = 0; i < DAYS_IN_ALL_WEEK; ++i) {
            cal.add(Calendar.DAY_OF_YEAR, 1);
            mDateDisplayValues[i] = (String) DateFormat.format("MM.dd EEEE", cal);
        }
        mDateSpinner.setDisplayedValues(mDateDisplayValues);
        mDateSpinner.setValue(DAYS_IN_ALL_WEEK / 2);
        mDateSpinner.invalidate();
    }

    // 更新AM/PM选择器
    private void updateAmPmControl() {
        if (mIs24HourView) {
            mAmPmSpinner.setVisibility(View.GONE);
        } else {
            int index = mIsAm ? Calendar.AM : Calendar.PM;
            mAmPmSpinner.setValue(index);
            mAmPmSpinner.setVisibility(View.VISIBLE);
        }
    }

    // 更新小时选择器
    private void updateHourControl() {
        if (mIs24HourView) {
            mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW);
            mHourSpinner.setMaxValue(HOUR_SPINNER_MAX_VAL_24_HOUR_VIEW);
        } else {
            mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_12_HOUR_VIEW);
            mHourSpinner.setMaxValue(HOUR_SPINNER_MAX_VAL_12_HOUR_VIEW);
        }
    }

    // 设置日期时间变化的回调函数
    public void setOnDateTimeChangedListener(OnDateTimeChangedListener callback) {
        mOnDateTimeChangedListener = callback;
    }

    // 通知日期时间变化
    private void onDateTimeChanged() {
        if (mOnDateTimeChangedListener != null) {
            mOnDateTimeChangedListener.onDateTimeChanged(this, getCurrentYear(),
                    getCurrentMonth(), getCurrentDay(), getCurrentHourOfDay(), getCurrentMinute());
        }
    }
}